Non-obvious intentional feeding really needs to be taken more seriously

i.e. I just had a player in ranked who was upset we wouldn't surrender, so they started running into the enemy ADC and just walking circles around them while they killed him, then typed out 'lol lag' in chat. They did this three times in a row. Someone on the other team told us that this player did the exact same thing in their previous game, so this is at least their second time doing it.

This shit happens constantly in ranked, especially around Diamond V. Something needs to be done to improve this situation.